Container with a butt seam



June 18, 1963 w. s. SCHNEIDER 3,094,269

CONTAINER WITH A BUTT SEAM Filed May 1, 1959 (mmmnnu um:

unmummnnm ATTORNEQS'.

INVEN TOR. I mL/HM 5. 5c/0vE/0E/g United States Patent M 3,094,269CONTAENER WITH A BUTT SEAM William S. Schneider, Glendale, Califi,assignor, by direct and mesne assignments, to Packaging Frontiers Inc.,a corporation of Delaware Filed May 1, 1959, Ser. No. 810,304 5 Claims.(Cl. 22986) The present invention relates generally to containers orpackages; and more especially to flexible containers that are made fromsheets or webs of thin flexible materials, such as paper, foil, plastic,or combinations of these materials.

In the .art of making containers, it is well known to start with a webwhich is unwound from a roll as a flat element and is fed continuouslyinto a machine wherein the web is shaped around a tubular mandrel toassume a tubular formation. Portions along opposite sides of the web arebrought together in forming the tube and are subsequently joinedtogether in a suitable manner to form a seam that extends longitudinallyof the web. One wellknown type of seam is the overlapping seam in whichmarginal portions along opposite edges of the web are brought intooverlapping relation and then sealed together. This seam and apparatusfor making it are well known in the art and are disclosed in US. PatentNo. 2,741,079 issued April 10, 1956, to R. Rausing for Apparatus forContinuous Production of Filled and Sealed Tetrahedral Packages of Paperor the Like.

After the web is formed into a tube, the material to be packaged is fedinto the tube. The individual packages are then completed by makingspaced seals extending transversely across the tube at intervals alongthe length of the tube. If successive transverse seals are all locatedin a common plane, the package produced is a flat envelope-type package.If the successive seals are located in planes at substantially 90 to oneanother, as is shown in the Rausing patent referred to above, thepackages produced have a tetrahedral shape. Packages of other shapes maylikewise be produced from the tube into which the flat web has beenformed.

The overlapping type of longitudinal seam has been widely used for manyreasons in making packages from a continuous web. However, a seam ofthis type has some serious disadvantages. For example, in the case ofwebs which are sealed by the application of heat and pressure, it isnecessary to use a web which is heat-sealable on two sides. Thisrequirement exists because of the overlapping character of the seam.This requirement imposes a severe limitation upon the range of materialsthat may be used for making containers since by far the largestproportion of webs now commercially available for making containers areheat-sealable on one side only.

Another serious disadvantage of a longitudinal seam of the overlappingtype is a condition commonly referred to in the trade as wicking. Tounderstand this problem it should be realized that the web or stock fromwhich is made a container of the type with which we are here concerned,is frequently of a character to absorb liquids. In the case of laminatedwebs consisting of two or more layers of different materials, one of theinner layers, contributing thickness and stiffness to the Web, may bemoderately absorbent. Such a layer is usually made of paper or othercellulosic material. It is common practice to coat the absorbent layerwith a layer of moistureresistant material which makes the webheat-sealable and prevents direct contact between the liquid contentsand the absorbent layer. However, when the conventional overlapping sealis used, this barrier to moisture, provided by the moisture-resistantinner coating is broken at the cut edge of the stock which is exposed onthe inside of the container to the liquid contents. At this cut edge,the

3,094,269 Patented June 18, 1963 absorbent layer can absorb enoughliquid that its softens or disintegrates, weakening the longitudinalseam and eventually causing it to leak.

In general, the longitudinal seam presents something of a problem in acontainer made from a continuous web because of the desire to make theseam as inconspicuous as possible. In a container of tetrahedral shapeit is desired to have the seam entirely on one side of the container. Itwill be noted that in the container of this shape disclosed in theRausing patent mentioned above, the longitudinal seam crosses part oftwo of the four sides of the container and as a result is always visibleto some extent. When the seam is on one side only, it can be hidden byresting the container upon that side. A particular advantage of thisconstruction is that the entire area of the remaining three sides isfree for printing, art work, or similar displays. To locate thelongitudinal seam entirely on one side of a tetrahedron, the seam muststart at one end of one of the transverse seals. When the seam is formedby overlapping the Web and is located at the end of a transverse seal afold at the end of the transverse seal must be made through three orfour thicknesses of the web. This thickness of stock resists folding andis hard to perform satisfactorily in high speed machines. There is amarked tendency for the seam to break open at such a fold, causing thepackage to leak.

Therefore it becomes a general object of my invention to provide acontainer, made from a continuous web of thin flexible material, with alongitudinal seam such that no cut edge of the web is exposed to thecontents and therefore the container wall is not subject to wicking orthe absorption of liquid from the contents.

Another object of the invention is to provide a container with alongitudinal seam that has the above advantages and that permits thecontainer to be manufactured from webs that can be heat sealed on oneside only.

A further object of the invention is to provide a longitudinal seamconstruction which enables the container to be made with transverseseals requiring folding of only .a single thickness of web and formed bythe application of heat and pressure for closing the ends of the tube.

Another object of the invention is to provide a container having alongitudianl seam which leaves the maxi mum number of sides of thecontainer free for printing, art work, or the like.

Another object of the invention is to provide a seam construction for acontainer of the character described which permits incorporation in theseam of novel means for progressively opening the container at the seam.

The above objects of the invention have been attained in a preferredform of container comprising a web of thin, flexible material formedinto a tube with opposite longitudinal edges of the web brought intoabutting relation. A sealing strip is located inside the tube and issealed to marginal portions of the web adjoining both edegs to form alongitudinal seam extending for the length of the tube and closing thetube. The package is completed by spaced closure means at each end ofthe tube. While not necessarily limited to any specific means, suchclosure preferably consists of marginal portions of the tube heat sealedtogether inside-face-to-inside-face.

.Such a seam and end seal can be provided with a Web which is heatsealable on one side only by placing the heat sealable side on theinside of the container. The sealing strip is heat sealable on two sidesand consequently seals not only to the marginal portions of the webadjoining the abutting edges but also seals to the op posite wall of thecontainer where the strip passes through the transverse seals at theends of the packages.

I prefer to incorporate in the sealing strip a tear string which islocated centrally of the strip and which may be pulled out between theabutting edges of the web to rip the sealing strip apart along theseedges. The tear string is particularly adapted to controlled orprogressive opening of the package which, in the case of a tetrahedron,for example, permits the opening through which the contents are removedto be progressively expanded as the level of the contents is lowered.

When the transverse end seals lie substantially in planes of 90 to eachother to form a tetrahedral shaped container, the longitudinal seam islocated in the tube to extend from one lateral end of one end sealacross a single triangular side of the container and centrally acrossthe other end closure. In this position the seam can be located entirelyon the bottom of the container.

A butt type longitudinal seal of this character produces a neat,unobvious seam which contributes materially to a pleasing appearance toa package. It also permits a design or a text printed on the exteriorsurface of the container to occupy three of the four sides within anybreak or interruption caused by a seam and even extend across the seamwith only a minimum interruption since the surface containing the seamis substantially continuous.

How the above objects and advantages of my invention, as well as othersnot specifically mentioned, are attained will be more easily understoodby reference to the following description and to the annexed drawing inwhich:

FIG. 1 is a side elevation of a tetrahedral container embodying myinvention.

FIG. 2 is a plan view of the container of FIG. 1.

FIG. 3 is an enlarged fragmentary section on line 33 of FIG. 1, thethickness of the web and sealing strip being exaggerated for purposes ofillustration.

FIG. 4 is an enlarged fragmentary section on line 44 of FIG. 1, thethicknesses of the web and strip again being exaggerated.

FIG. 5 is an enlarged fragmentary side elevation of the upper corner ofthe container of FIG. 1.

FIG. 6 is a view similar to FIG. 5 illustrating an initial step inopening the container.

' 'FIG. 7 is a diagram illustrating steps in the formation of thelongitudinal seam.

FIG. 8 is a plan view of an opened tetrahedral container illustratinghow the opening may be progressively expanded.

FIG. 9 is a perspective of a fiat container embodying my invention.

Referring now to the drawing, there is shown in FIGS. 1 and 2 acompleted container C of tetrahedral shape illustrating a preferredembodiment of the invention. The construction of the container is mosteasily understood by describing various steps involved in themanufacture of the container, as will now be done.

Making containers of various shapes from a continuous web is so wellknown in the art as to make unnecessary the recitation in detail of allthe steps involved in the forming and/or shaping of the web andappaartus therefor. Commonly, the operation of forming containers startswith unrolling the web as a continuous, planar member from a roll. Theweb is then formed around a mandrel of suitable size and shape toproduce a tubular member. Such an operation is disclosed in RausingPatent No. 2,741,079 mentioned above.

The web W is illustrated diagrammatically in FIG. 7 after it has assumedthis tubular shape. The web W may be considered as being any one of anumber of thin, flexible materials that is heat scalable on the facewhich becomes the inner face of the tube and the subsequent container.Of course the invention is not limited to materials which are heatscalable on one face only. Usual and typical materials are paper stockcoated with a waterresistant sealing compound, of a laminated stockwhich includes a core layer of paper, a coating of synthetic resin or aplastic substance, and an outer layer of metal foil.

Various other combinations of material are available and may be used buta typical laminated web W of this latter construction is illustrated inFIG. 4.

The metal foil 11 is placed on the outside of the completed package andnormally carries printing, art work, or the like that contributes to theappearance of the package. The coating of synthetic resin 12 is placedon the inside of the package where it provides a barrier to absorptionof moisture by paper core 14 from the contents of the package. The layerof paper or board 14 is absorbent material and must be protected fromreceiving moisture from the contents of the container if the seal is toremain strong. The inner coating 12 is usually of such a character as torender the inner face of the web heat scalable by the application ofheat and pressure.

When the web is formed into a tubular shape as shown in FIG. 7, thelongitdinal edges 15 and 16 at opposite sides of the web are broughttogether in abutting relation as shown in FIG. 4. In this position,marginal portions 17 and 18 of the web adjoining edges 15 and 16respectively, both overlie sealing strip 20. The sealing strip is acontinuous member placed inside the tube and extending parallel toabutting edges 15 and 16. When the parts are in the position shown inFIG. 7, the marginal portions 17 and 13 of the web adjoining edges 15and 16 can be sealed to strip 20 by the application thereto of heat andpressure. This may be accomplished by a member 21 applying pressure inthe direction of arrow 22 to press the web against sealing strip 20. Thesealing strip may be backed up by suitable abutment member 24 whichtypically may be the mandrel around which web W is shaped. It will beunderstood that heat may be applied to the joint by any suitable means,as by a heated member 21 or by a high frequency electromagnetic field.

Sealing strip 20 is itself scalable on two sides and may be of anyconstruction or material providing this characteristic. As one exampleof a suitable material, but without limiting the invention thereto,sealing strip 20 may be a homogeneous strip of thermoplastic resin suchas polyethylene. Also by way of example, another suitable sealing stripis a product marketed by Minnesota Mining and Manufacturing Companyunder the trade name Scotch- Pak and which is a polyester film coated onboth sides with a sealing coat which will seal to itself and also tomany other laminated stocks commonly used for making packages orcontainers. Either of these sealing strips are moisture resistant andadequately protect the cut edges 15 and 16 of the web from any contactwith moisture inside the completed container.

To prevent the sealing strip from adhering to abutment 24, the lattermember may be made from or coated with some substance to which the stripdoes not adhere, for example, a tertafiuoroethylene polymer, commonlyknown as Teflon.

Each package is completed by compressing the tube in a zone extendingtransversely across the tube to bring together opposing walls of thetube. The web material being heat sealable on the inside face, atransverse seal is made by the application of heat and pressure at thetime of compressing the walls to bring them together in faceto-facerelation. As a result, the walls are sealed togetherinside-face-to-inside-face. In its broader aspect the present inventionis not necessarily limited to a transverse seal of this character sinceunder some circumstances other suitable types of closure may be used,including pressure sensitive or water soluble adhesives, staples, and soon.

These transverse seals are ordinarily formed one at a time and insuccession at spaced intervals along the length of the tube. Since eachtransverse seal closes the lower end of the tube, a charge of contentscan then be placed in the tube above the seal. Then another transverseseal is placed across the tube above the contents to complete thepackage and enclose the contents. Individaul packages are severed fromthe tube by cutting through the tube at one of the seals. Each of thetransverse seals thus provides a portion of the sealed area 25 or 26located at each end of the tube segment which becomes an individualpackage. As seen in FIGS. 1 and 2, the two end seals 25 and 26 aresubstantially in planes at approximately 90 to each other, thusproducing a four-sided container having four similar triangular sides.

Because sealing strip is heat scalable on both sides or faces, it sealsreadily either to itself where it passes through seal or to the opposingwall of the container where it passes through end seal 26. Thischaracteristic insures that both end seals are unbroken by the presenceof strip 20 and that the contents of the container will not leak or siftout through any minute opening at or around the location of the sealingstrip as it passes through the end sealed areas.

In placing the transverse seals, the seal 25 is so located that strip 20is folded back upon itself where it passes through the seal 25 and isthus located at one lateral end of the elongated sealed area. From thislocation the longitudinal seam formed by the sealing strip passes overonly one triangular side of the container, as shown in FIG. 2. In asymmetrical package the seam bisects this side of the package.Accordingly, the seam and the sealing strip are located centrally of theother end seal 26.

To obtain the most favorable appearance, the container as so fardescribed can be displayed with the longitudinal seam completely hidden.This is done by resting the package on the side which is shown uppermostin FIGS. 1 and 2. The one side crossed by the seam is thus at the bottomof the package where the seam is not seen. The other three sides of thecontainer present smooth, uninterrupted surfaces to receive printing ordesigns of any character without any discontinuity created by thepresence of the longitudinal seam crossing a portion of the side. A buttseam as described, when located at an end of one of the tnansverseseals, eliminates any problem of folding through multiple thicknesses,and produces a completely reliable seal at the ends of the container.

In a preferred embodiment of my invention, sealing strip 20 includes atear string attached to the inner face of the sealing strip andextending longitudinally of the strip midway between its longitudinaledges. In making the container, this tear string is located directlybeneath the abutting edges 15 and 16 of the web. While these abuttingedges may be in contact with each other, it is preferred that they benot in contact with each other but very closely spaced'(FIG. 4) when thetear string is provided. This tear string can then be more easily pulledout between the two edges, ripping apart the sealing strip to provide anopening in the container wall. This is facilitated by making the sealingstrip of lesser strength than the web constituting the container wall.

As shown particularly in FIGS. 3 and 5, the tear string 30 crossessealed area 25 at a position very close to one lateral edge. At thislocation on the container, the edges 15 and 16 of the web are disposedsubstantially in a common plane and the tear string can be pulled outfrom between them by tearing through only the thickness of the sealingstrip.

When the completed container is severed from the tube by making atransverse cut in sealed area 25, the tear string is cut flush with theend of the container. In order to free it for purposes of opening thepackage, sealed area 25 is formed with a line of Weakness whichintersects the tear string, preferably at or near the inner end of thesealed area. A preferred means for defining this line of weakness is arow of small, closely spaced perforations 32 commencing at the outer endof the container and extending inwardly across sealed area 25 tointersect the tear string. The sealed area can be torn with relativecase from one perforation to the next, permitting a triangular corner 34to be torn off as shown in FIG. 6. The terminal portion of tear string30 is now free and the string can be pulled from left to right in FIG.

1 along the longitudinal seam and between edges 15 and 16 to tear thesealing strip 20.

It will be noticed that the opening 35 made in the container starts atthe highest point of the container so that none of the contents spill orleak out when the opening is first made. The size of the opening can bemade as large as desired by pulling the tear string a greater or lesserdistance from the seal 25. This is a particularly useful characteristicin the case of a food product packaged in the container which can beeaten with a spoon. As the contents are removed and their level drops,the opening can be progressively enlarged as indicated at 35a and 35b inbroken lines in FIG. 8 to provide continuing ease of access to allportions of the container.

In the case of a tetrahedral package made of transparent material, it isdifficult to measure by eye the quantity remaining in the package, whenpartially emptied, because the volume of the contents is not in directproportion to the height of the contents above the bottom. When desiredor necessary to make a close estimate of the volume of the contents, ascale 40 is printed on the outside of the container. Such a scale may begraduated in any unit of volume, such as ounces, cubic centimeters, andthe like. A scale of this character permits the user to measure aspecific quantity of the contents emptied from the container or todetermine from inspection by reference to the scale the volume orquantity of the contents remaining in the partially emptied container.Obviously, because of the shape of the container the utility of such ascale depends upon its accurate positioning upon the package and moreparticularly with respect to one of the seals. While in general thescale must be positioned properly between the two end seals 25 and 26,it more particularly is located at a fixed distance from the end seal 25or 26 to measure the contents. Printing may also be placed on the Web ina predetermined position to be adjacent the line of weakness establishedby perforations 32 which are formed at the time that sealed area 25 isformed. Such printing would include instructions to the user for freeingthe end of the tear string and using it to open the container.

In some of its aspects, my invention can be embodied in a flat orenvelope type container having two principal sides, as illustrated inFIG. 9. In this type of container, the end seals 37 and 38 aresubstantially in a common plane instead of being rotated with respect toone another as is the case with end seals 25 and 26. The longitudinalseam is formed in the manner described above and is located at the endof at least one of the transverse seals. A section through the end oftransverse seal 37 would appear as in FIG. 3. However, since the twoseals 37 and 38 are in the same plane, the longitudinal seam continuesdown an edge of the package, the abutting edges of the web beingindicated at 39. Hence the sealing strip 20 in this type of packagecrosses both end seals 37 and 38. A row of perforations 32 or othermeans establishing a line of weakness may be provided to facilitatefreeing one end of the tear string, as already described. The package isthus opened along one edge rather than across one of its principal facesand the two large exposed surfaces on the package are left free anduninterrupted for printing, art Work and the like.

From the foregoing it will be realized that various changes in thedesign and construction of packages are possible within the scope of myinvention; and accordingly it is to be understood that the foregoingdescription is considered to be illustrative of rather than limitativeupon, the invention as defined by the appended claims.

I claim:

1. A filled package comprising a tube formed from a Web of flexiblepackaging material and being heat-scalable on the inside, thelongitudinal edges of the web being contiguous and secured together by asealing strip on the inside of the tube, said strip being heat-scalableon both its faces and lapping and heat-sealed to the longitudinalmargins of the web thereby providing a longitudinal tube seam, each endof the tube being closed by a transverse inside-face-to-inside-face heatseal, one of said transverse seals comprising an end portion of the tubeflattened in such a plane that the portion of the Web included thereinis folded on a fold line at one end of said one transverse seal and thelongitudinal edges of said portion of the Web are located at the cornerof the package at the other end of said one transverse seal with the endportion of said strip at said corner folded on a fold line at said otherend of said one transverse seal, a tearing member secured to said stripon the inside thereof extending longitudinally of the stripsubstantially in register with said contiguous longitudinal edges of theWeb, the interengaging faces of said folded end portion of said stripbeing heat-sealed together about the tearing member with said tearingmember terminating at the ends of said strip within said transverseseals, and a line of weakness at said corner extending inward from therespective end of the tube across said one transverse seal and acrossthe respective end portion of said strip to provide a tear-off cornerportion of said one transverse seal and said strip for freeing therespective end of the tearing member whereby the tearing member alongwith the tear-oif corner portion heat-sealed thereabout may be grippedand pulled to tear the strip between the contiguous edges of the Web.

2. A filled tetrahedron-shaped package comprising a tube formed from aweb of flexible packaging material and being heat-scalable on theinside, the longitudinal edges of the web being contiguous and securedtogether by a sealing strip on the inside of the tube, said strip beingheat-sealable on both its faces and lapping and heat-sealed to thelongitudinal margins of the web thereby providing a longitudinal tubeseam, each end of the tube being closed by a transverseinside-face-to-inside-face heat seal, each of said transverse sealscomprising a flattened end portion of the tube, one of said transverseseals being flattened in such a plane that the portion of the webincluded therein is folded on a fold line at one end of said onetransverse seal and the longitudinal edges of said portion of the webare located at the corner of the package at the other end of said onetransverse seal, the

end portion of said strip at said corner being folded genorally in halfon a longitudinal fold line at said other end of said one transverseseal with the adjacent faces of the folded end portion being heat-sealedtogether, the other transverse seal being flattened in a plane at suchan angle to the first-mentioned plane as to form a tetrahedron-shapedpackage with four triangular sides, and said longitudinal seam includingsaid strip extending from said corner across one triangular side only ofthe package and across the other transverse seal between the ends of thelatter, the other end portion of said strip lying flat and unfoldedwithin said other transverse seal.

3. A filled tetrahedron-shaped package as set forth in claim 2 furthercomprising a tearing member secured to said strip on the inside thereofextending longitudinally of the strip substantially in register withsaid contiguous longitudinal edges of the web adapted for being pulledto tear the strip between the contiguous edges of the Web.

4. A filled package as set forth in claim 3 wherein the adjacent facesof the folded end portion of the strip are heat-sealed together aboutthe tearing member and said tearing member terminates at the ends ofsaid strip within said transverse seals and wherein a line of weaknessis provided at said corner extending inward from the respective end ofthe tube across said one transverse seal and across the respective endportion of said strip to provide a tear-off corner portion of said onetransverse seal and said strip for freeing the respective end of thetearing member.

5. A filled package comprising a tube formed from a web of flexiblepackaging material and being heat-sealable on the inside, thelongitudinal edges of the web being contiguous and secured together by asealing strip on the inside of the tube, said strip being heat-sealableon both its faces and lapping and heat-sealed to the longitudinalmargins of the web thereby providing a longitudinal tube seam, each endof the tube being closed by a transverse inside-face-to-inside-face heatseal, each of said transverse seals comprising a flattened end portionof the tube, each transverse seal being flattened in the same plane withthis plane such that the portion of the web included in each transverseseal is folded on a fold line at one end of the transverse seal and thelongitudinal edges of said portion of the web are located at the cornerof the package at the other end of the transverse seal, said strip beingfolded throughout its length on a fold line defining one side edge ofthe package and said strip having its end portions included in thecorners of the packages at the ends of said side edge of the package, atearing member secured to said strip extending longitudinally of thestrip within the fold of the strip, the interengaging faces of saidfolded end portions being heat-sealed together about the tearing memberwith said tearing member terminating at the ends of said strip withinsaid transverse seals, and a line of Weakness at one of said cornersextending inward from the respective end of the tube across therespective transverse seal and the respective end portion of said stripto provide a tear-off corner portion of this transverse seal and thestrip for freeing the respective end of the tearing member whereby thetearing member along with the tear-off corner portion heat-sealedthereabout may be gripped and pulled to tear the strip along the foldthereof.

References Cited in the file of this patent UNITED STATES PATENTS180,773 Magruder et a1 Aug. 8, 1876 1,155,740 Lacroix et al. Oct. 5,1915 1,853,013 Brady Apr. 5, 1932 1,936,417 Ware Nov. 21, 1933 1,978,035Thom Oct. 23, 1934 2,169,936 Wagner Aug. 15, 1939 2,226,936 Flood Dec.24, 1940 2,565,622 Orr Aug. 28, 1951 2,699,285 Bell et al. Jan. 11, 1955FOREIGN PATENTS 246,680 Switzerland Oct. 1, 1947

1. A FILLED PACKAGE COMPRISING A TUBE FORMED FROM A WEB OF FLEXIBLEPACKAGING MATERIAL AND BEING HEAT-SEALABLE ON THE INSIDE, THELONGITUDINAL EDGES OF THE WEB BEING CONTIGUOUS AND SECURED TOGETHER BY ASEALING STRIP ON THE INSIDE OF THE TUBE, SAID STRIP BEING HEAT-SEALABLEON BOTH ITS FACES AND LAPPING AND HEAT-SEALED TO THE LONGITUDINALMARGINS OF THE WEB THEREBY PROVIDING A LONGITUDINAL TUBE SEAM, EACH ENDOF THE TUBE BEING CLOSED BY A TRANSVERSE INSIDE-FACE-TO-FACE HEAT SEAL,ONE OF SAID TRANSVERSE SEALS COMPRISING AN END PORTION OF THE TUBEFLATTENED IN SUCH A PLANE THAT THE PORTION OF THE WEB INCLUDED THEREINIS FOLDED ON A FOLD LINE AT ONE END OF SAID ONE TRANSVERSE; SEAL AND THELONGITUDINAL EDGES OF SAID PORTION OF THE WEB ARE LOCATED AT THE CORNEROF THE PACKAGE AT THE OTHER END OF SAID ONE TRANSVERSE SEAL WITH THE ENDPORTION OF SAID STRIP AT SAID CORNER FOLDED ON A FOLD LINE AT SAID OTHEREND OF SAID ONE TRANSSVERSE SEAL, A TEARING MEMBER SECURED TO SAID STRIPON THE INSIDE THEREOF EXTENDING LONGITUDINALLY OF THE STRIPSUBSTANTIALLY IN REGISTER WITH SAID CONTIGUOUS LONGITUDINAL EDGES OF THEWEB, THE INTERENGAGING FACES OF SAID FOLDED END PORTION OF SAID STRIPBEING HEAT-SEALED TOGETHER ABOUT THE TEARING MEMBER WITH SAID TEARINGMEMBER TERMINATING AT THE ENDS OF SAID STRIP WITHIN SAID TRANSVERSESEALS, AND A LINE OF WEAKNESS AT SAID CORNER EXTENDING INWARD FROM THERESPECTIVE END OF THE TUBE ACROSS SAID ONE TRANSVERSE SEAL AND ACROSSTHE RESPECTIVE END PORTION OF SAID STRIP TO PROVIDE A TEAR-OFF CORNERPORTION OF SAID ONE TRANSVERSE SEAL AND SAID STRIP FOR FREEING THERESPECTIVE END OF THE TEARING MEMBER WHEREBY THE TEARING MEMBER ALONGWITH THE TEAR-OFF CORNER PORTION HEAT-SEALED THEREABOUT MAY BE GRIPPEDAND PULLED TO TEAR THE STRIP BETWEEN THE CONTIGUOUS EDGES OF THE WEB.